SUMMARY Fifty two psoriatic patients were treated with a new experimental fluorescent lamp (Philips TL-01) emitting a narrow band at 311 2 nm (UVB) which had the advantage of a reduction in burning and carcinogenic wavelengths when compared with conventional broad band UVB therapy. Conclusions: Monochromatic 308-nm excimer laser treatment appears to be effective and safe for psoriasis. 311 nm UVB phototherapy: an effective treatment for psoriasis. 311 nm UVB phototherapy: an effective treatment for psoriasis.